Open RegEdit with admin rights (use search in Start menu, then Ctrl+Shift+press on it). Set 'Perform scaling on' to 'GPU' in NVIDIA Control Panel. Below is a fix that requires using RegEdit, so you may want to create a restore point before doing it to feel safer. Buggy NVIDIA Control Panel of the latest drivers resets scaling to 'Full-screen' whenever you set it to 'Aspect ratio', at least for me. This topic explains how to make 640*480 and similar resolutions not stretch horizontally on a wide screen. I'll copy the text here, in case the link breaks in the future: So, it's an old Nvidia bug, not yet fixed after years! Well, I finally found this old post about it: The option 'Aspect Ratio' kept getting back to 'Full-screen' for no reason. However, I couldn't manage to obtain this from the Nvidia panel in 'Adjust desktop size and position'. To obtain that, I usually have to simply change my graphic settings. When playing old 4:3 games fullscreen, I often prefer black bars, more than an ugly stretched picture. I'm posting this solution here to help other goggers with my same problem.
